1. Field of the Invention
The invention relates to a vehicle, and more particularly to a technique for further improving fuel economy while inhibiting battery degradation in a vehicle capable of coasting, that is, running in a state with an engine brake force reduced with respect to that in an engine brake running mode.
2. Description of Related Art
A coasting mode in which an engine brake force is reduced with respect to that in the engine brake running mode, in which the engine is coupled to the wheels and the engine brake is activated, has been considered for extending the running distance and improving fuel economy over those in the engine brake running mode. In the apparatus described in Japanese Patent Application Publication No. 2002-227885 (JP-2002-227885 A), two control modes, namely, the first coasting mode in which the engine rotation is stopped and the second coasting mode in which the vehicle runs, while the engine rotates are suggested by way of example. More specifically, in the first coasting mode, free-run coasting is performed in which the clutch is released, the engine is disconnected from the wheels, fuel supply to the engine is stopped, and engine rotation is stopped. In the second coasting mode, neutral coasting is performed in which the clutch is released, the engine is disconnected from the wheels and in this state fuel is supplied to actuate (cause self-rotation) the engine. Either of those coasting modes is executed under certain conditions practically in the same way.
However, JP-2002-227885 A describes a steering angle of a steering wheel as a coasting execution condition, and when the steering angle is equal to or less than a predetermined angle, the two coasting modes are executed in the same way.